Different Concentrations Of Heavy Metals Research Articles

In vitro and in vivo screening of bacterial species from contaminated soil for heavy metal biotransformation activity

Heavy metals (HMs) are widely used in various industries. High concentrations of HMs can be severely toxic to plants, animals and humans. Microorganism-based bioremediation has shown significant potential in degrading and detoxifying specific HM contaminants. In this study, we cultivated a range of bacterial strains in liquid and solid nutrient medium containing different concentrations of different HMs to select and analyze bacteria capable of transforming HMs. The bacterial strains most resistant to selected HMs and exhibiting the ability to remove HMs from contaminated soils were identified. Then, the bacterial species capable of utilizing HMs in soil model experiments were selected, and their ability to transform HMs was evaluated. This study has also generated preliminary findings on the use of plants for further removal of HMs from soil after microbial bioremediation. Alcaligenes faecalis, Delftia tsuruhatensis and Stenotrophomonas sp. were selected for their ability to grow in and utilize HM ions at the maximum permissible concentration (MPC) and two times the MPC. Lysinibacillus fusiformis (local microflora) can be used as a universal biotransformation tool for many HM ions. Brevibacillus parabrevis has potential for the removal of lead ions, and Brevibacillus reuszeri and Bacillus safensis have potential for the removal of arsenic ions from the environment. The bacterial species have been selected for bioremediation to remove heavy metal ions from the environment.

Contamination status, risk assessment, and control measures of heavy metals in tuber crops

Tuber crops (TCs) are an important food source for people; however, the contamination of TCs by heavy metals (HMs) has not received sufficient attention. In this study, 253 batches of TCs samples containing HMs (Pb, Cd, Cr, Hg, As) were collected to investigate the contamination status and health risks. The results showed that different TCs contained different concentrations of HMs, while cassava exhibited the highest levels of each HM. In terms of health risks, the non-carcinogenic and carcinogenic risks associated with TCs consumption were in the “Negligible risk”, “Cautionary risk”, respectively. On the economic and age scales, the health risk concerning TCs consumption varied. The health risks increased when cassava was included in the diet. Field experiments were conducted to explore the factors influencing the accumulation of HMs and propose measures to control HMs contamination. When measures were taken to intervene in the factors (soil HMs, soil organic matter, soil pH and cassava variety) affecting the HMs content in cassava, the health risks were significantly reduced, with a maximum reduction of 43.71% and 17.50% in non-carcinogenic and carcinogenic risks, respectively. This study provides ideas for the pollution management of HMs in TCs.

Assessment of heavy metal contamination in the groundwater of Gujarat, India using the heavy metal pollution index

Groundwater serves as a vital water source for a significant population in the Gujarat region of India. However, substantial contamination from heavy metals, pose a serious threat to human health through various pathways, including drinking water. The rapid industrial and agricultural growth in recent years has exacerbated heavy metal pollution in the state. This study focuses on assessing the heavy metal contamination in Gujarat's groundwater using the Heavy Metal Pollution Index (HPI). The research covers the entire state, considering its diverse physical, climatic, topographical, and geographical conditions. The HPI scores obtained from individual studies highlight the extent of pollution caused by heavy metals. The overall findings underscore the severe problem of heavy metal contamination in Gujarat's groundwater and the associated health risks. Various other pollution indicators, including the Heavy Metal Evaluation Index, Degree of Contamination, Metal Index, and Water Pollution Index are discussed as tools to assess contamination levels. These indices compare concentrations of different heavy metals with established limits to determine the pollution level. The goal is to provide valuable insights for investors and policymakers in formulating strategies to manage and reduce heavy metal contamination across the state. Additionally, the review explores effective, environmentally friendly, and economically viable treatment techniques to remove heavy metals from aquatic systems, safeguarding the environment. By employing pollution indicators and remedial actions, this study aims to guide efforts in mitigating the impact of heavy metal contamination in Gujarat's groundwater.

HEMATOLOGICAL VARIATIONS AND ASSESMENT OF HEAVY METALS IN SIDH SPARROW (PASSER PYRRHONOTUS) AS A BIOINDICATOR IN PUNJAB AREAS OF PAKISTAN

Sindh sparrows, prevalent in Sindh region of Pakistan, are non-migratory birds abundant in human-inhabited areas globally, except Antarctica. Given their close association with human settlements, these birds serve as crucial indicators for biological monitoring in regions affected by pollution. This study focused on assessing the hematological parameters and heavy metal concentrations in various organs of Sindh sparrows in the Punjab regions of Pakistan. The collected blood samples underwent analysis for hematological indices and heavy metal concentrations. The results indicated variability in hematological analysis of sparrows. Fluctuations were observed in the concentrations of different heavy metals, with significant differences in zinc and iron, while chromium, cadmium, and nickel concentrations showed non-significant differences. The patterns of heavy metal accumulation revealed higher concentrations of chromium, nickel, and iron in the liver, contrasting with the cadmium and zinc in kidneys. In conclusion, significant correlations were observed among the concentrations of Zinc, Chromium, Cadmium, Nickel, and Iron in kidney, liver, and muscles of both male and female Sindh sparrows. The findings underscore the need for further comprehensive studies to assess heavy metal accumulation in birds, highlighting the urgency to address environmental pollution that poses risks to avian species and human populations worldwide.

Assessment of Heavy metals in Sediments, Water and Carias gariepinus from Alau Dam, Borno State Nigeria

Alau dam attracts commercial fishing and farming activities creating a booming market for individuals involved in the fish and vegetable businesses. The lake having flowed into several towns and villages coupled with the socio-economic activities along its bank received effluents with different concentrations of heavy metals. The study was aimed at assessing the levels of selected heavy metals (Pb, Cd, Cr, As and Hg) concentrations in the sediments, water and Clarias gariepinus from Alau dam, Borno State, Nigeria. Samples were collected bi-weekly for 3 months and analyzed using standards methods. The result of the study indicates that heavy metal concentrations (Pb, Cd and Cr) in the sediments (2.120 ± 0.011, 1.004 ± 0.010 and 0.300 ± 0.010 mg/kg respectively) were all above USEPA permissible limits. The study further shows that exception of Cr (0.011 ± 0.007) all other analyzed metals were above NESREA limits. Additionally, the concentrations of Pb, Cd, Cr, As and Hg in the fish samples (1.020 ± 0.011, 0.940 ± 0.022, 0.001 ± 0.017, 0.010 ± 0.112 and 0.005 ± 0.033 mg/kg respectively) were within the NAFDAC limit. The Non-Cancer Risk (HQ were ˃ 1 in all calculated samples) and Cancer Risks (˃10-3 in all calculated samples) revealed high health risk from ingestion of the C. gariepinus from the study area. Furthermore, the BAF ratio shows Cd ˃ Pb ˃ Hg ˃ As ˃ Cr. The study recommends strict enforcement of NESREA regulations and a continuous monitoring of the levels of heavy metals concentration in the dam.

The Effect of EDTA on the Ability to Absorb Different Concentrations of Nickel, Cadmium, and Lead in Soil by Corn Plants

Background & Aims: The use of resistant and widely used species such as corn in agriculture and industry can be an effective solution for the bioremediation of soil pollutants, including heavy elements. The current research aimed to investigate the effect of EDTA on the ability to absorb different concentrations of heavy metals in the soil of corn plants in 2019. Materials and Methods: This research was conducted as a three-factor pilot design at concentrations of 0, 50, and 100 mg/kg in the greenhouse. The samples were analyzed using an atomic absorption device. The laboratory pilot design was based on Taguchi’s algorithm. Finally, transfer factor (TF), bioconcentration factor (BCF), and bioaccumulation coefficient (BAC) were calculated. Results: The results showed that different organs (root, stem, and leaf) show different levels of bioaccumulation under the influence of variable factors in different concentrations of heavy elements (nickel, cadmium, and lead). Also, there is a significant difference between the measured amounts of heavy elements in different organs of the corn plant (P≤0.05). The average TF levels for elements at concentrations of 50 and 100 mg/kg were 0.79 and 1.66 for nickel, 0.82 and 0.78 for cadmium and 1.361, 1.378, and 1.387 for lead. Based on the results, with the increase in nickel concentration, the absorption level increased, and with the increase in cadmium concentration, the absorption level decreased. Conclusion: The results of this research showed that it is possible to use EDTA to increase the efficiency of corn plants in absorbing heavy elements of nickel, cadmium, and lead.

Assessing the impacts of zeolite on water quality, growth performance, heavy metal content and health condition of farmed tilapia (Oreochromis niloticus)

The rapid expansion and intensification of tilapia (Oreochromis niloticus) aquaculture in Bangladesh results in an increasing tendency of administering more pharmaceuticals in fish health management. Hence, with the aim of investigating the effects of zeolite (a water and sediment treatment compound) on water quality, growth performance, hematology, gut microbial content, and heavy metal content of Oreochromis niloticus, an experiment was performed for 126 days in six experimental earthen ponds (each pond size is one decimal). The stocking density was 300 fry/decimal. Zeolite was applied directly into the water in treatment ponds at a rate of 200 g/decimal during pond preparation and 100 g/decimal/15 days intervals during the culture period as recommended by the manufacturing company. The results indicated that zeolite had a significant effect (p < 0.05) on all growth indices assessed in all three experimental stages (0–42 days, 43–84 days, 85–126 days) in treatment ponds compared to control ones, except condition factor (CF) at the first stage. Hematological results implied that the application of zeolite in treatment pond water had no significant effect on the red blood cell (RBC) and white blood cell (WBC) of experimental fish blood compared to the control. However, a significant effect on the blood glucose level and total viable count (TVC) of the experimental fish gut was observed due to the addition of zeolite in the treatment ponds. Zeolite supplementation in treatment pond water significantly reduced the concentrations of different heavy metals in pond sediment, water and fish flesh compared to the control. Therefore, zeolite could be recommended for administration in aquaculture. Further research is required to find out whether a higher or lower dose of zeolite improves the water quality, growth performance and health condition, and decreases the heavy metal content of fish or not.

Microbial community composition and degradation potential of petroleum-contaminated sites under heavy metal stress

Total petroleum hydrocarbons (n-alkanes), semi-volatile organic compounds, and heavy metals pose major ecological risks at petrochemical-contaminated sites. The efficiency of natural remediation in situ is often unsatisfactory, particularly under heavy metal pollution stress. This study aimed to verify the hypothesis that after long-term contamination and restoration, microbial communities in situ exhibit significantly different biodegradation efficiencies under different concentrations of heavy metals. Moreover, they determine the appropriate microbial community to restore the contaminated soil. Therefore, we investigated the heavy metals in petroleum-contaminated soils and observed that heavy metals effects on distinct ecological clusters varied significantly. Finally, alterations in the native microbial community degradation ability were demonstrated through the occurrence of petroleum pollutant degradation function genes in different communities at the tested sites. Furthermore, structural equation modeling (SEM) was used to explain the influence of all factors on the degradation function of petroleum pollution. These results suggest that heavy metal contamination from petroleum-contaminated sites reduces the efficiency of natural remediation. In addition, it infers that MOD1 microorganisms have greater degradation potential under heavy metal stress. Utilizing appropriate microorganisms in situ may effectively help resist the stress of heavy metals and continuously degrade petroleum pollutants.

Assessment and characterization of heavy metals resistance bacteria isolated in Southwestern Mediterranean coastal waters (Bou-Ismail Bay): Impacts of anthropogenic activities

Bacteria present in the marine environment can cause ecological risks and seriously impact human health through direct contact or the food chain. This paper examines bacterial resistance to heavy metals and anthropogenic inputs' influence in four Bou-Ismail Bay regions (Algerian coast). The study was conducted from May to October 2018. High levels of resistance of total flora and total coliform were observed respectively for zinc (29.5 %, 30.5 %), copper (26.2 %, 20.7 %), mercury (17.4 %, 17.2 %), lead (16.9 %, 14.2 %), and cadmium (8.9 %, 0 %). A total 118 metal resistant bacteria were identified. All isolates were tested against 5 heavy metals and 7 antibiotics. The isolates showed tolerance to different concentrations of heavy metals ranging from 12.5 to 6400 μg/ml and exposed a co-resistance to the other heavy metals. The majority of strains were multi-resistant to heavy metals and antibiotics. Therefore, the bacteria isolated from Bou-Ismail Bay are highly resistant to heavy metals and antibiotics.

Effect of Heavy Metals on the Abundance of Bacteria of the Genus &lt;i&gt;Аzotobacter&lt;/i&gt; in Gray-Brown Soils of the Аbsheron Peninsula

The effect of different concentrations of heavy metals in gray-brown soils of the Absheron Peninsula on the abundance of bacteria of the genus Azotobacter has been studied. The indicators of the total number of microorganisms and the abundance of bacteria of the genus Azotobacter were taken as informative indicators. It is shown that in the studied soil, with an increase in the concentration of heavy metals (TM) at all accounting periods, a decrease in the total number of microorganisms was observed compared with the control. The study of the abundance of bacteria g. Azotobacter of gray-brown soil showed that bacteria of this genus had sufficient resistance to the effects of TM. At concentrations of 1 MPC, no definite effect of heavy metals on bacteria of this genus was detected. However, with the action of TM at concentrations of 5 and 10 MPC, a decrease in the abundance of bacteria was observed in relation to the control. The studied metals according to their inhibitory effect, depending on the nature of pollutants, can be arranged in a row: Cr Pb Cu.

The relationships between heavy metals and bacterial communities in a coal gangue site

Coal is the main source of energy for China's economic development, but coal gangue dumps are a major source of heavy metal pollution. Bacterial communities have a major effect on the bioremediation of heavy metals in coal gangue dumps. The effects of different concentrations of heavy metals on the composition of bacterial communities in coal gangue sites remain unclear. Soil bacterial communities from four gangue sites that vary in natural heavy metal concentrations were investigated using high-throughput sequencing in this study. Correlations among bacterial communities, heavy metal concentrations, physicochemical properties of the soil, and the composition of dissolved organic matter of soil in coal gangue dumps were also analyzed. Our results indicated that Actinobacteriota, Proteobacteria, Chloroflexi, Acidobacteriota, and Gemmatimonadota were the bacterial taxa most resistant to heavy metal stress at gangue sites. Heavy metal contamination may be the main cause of changes in bacterial communities. Heavy metal pollution can foster mutually beneficial symbioses between microbial species. Microbial-derived organic matter was the main source of soil organic matter in unvegetated mining areas, and this could affect the toxicity and transport of heavy metals in soil. Polar functional groups such as hydroxyl and ester groups (A226-400) play an important role in the reaction of cadmium (Cd) and lead (Pb), and organic matter with low molecular weight (SR) tends to bind more to mercury (Hg). In addition to heavy metals, the content of nitrogen (N), phosphorus (P), and total organic carbon (TOC) also affected the composition of the bacterial communities; TOC had the strongest effect, followed by N, SOM, and P. Our findings have implications for the microbial remediation of heavy metal-contaminated soils in coal gangue sites and sustainable development.

DETERMINATION OF HEAVY METALS IN RAW MILK SAMPLES FROM DIFFERENT AREAS OF LAHORE

Study was conducted to analyze the concentration of different heavy metals including lead (Pb), Chromium (Cr), Zinc (Zn), Nickel (Ni), Manganese (Mn), Copper (Cu) and Iron (Fe) in raw milk samples from four towns of Lahore (Ravi Town, Data Gang Baksh Town, Iqbal Town and Town ship). 5ml of each sample was digested by using 14 ml HNO3 and after 30 minutes by adding 10 ml HCL04 for almost 2 hours at the temperature of 250° C until vine green or color less solution is formed. The concentration of heavy metals were determined by using Atomic Absorption Spectrophotometer. The mean concentration of all the heavy metals in all these towns except Zn and Fe were above the permissible limit set by WHO. The concentration of Mn and Ni was slightly high. Heavy metals having highest toxicity have higher contamination and lowest toxicity has lowest contamination. Highest toxic metal Pb (WHO standard is 0.02 ppm) contamination ranges between 3.3 ppm to 6.3 ppm among these towns. The lowest toxic heavy metal Zn (WHO standard is 60 ppm) having highest nutritious value, the contamination ranges lie between 1.41 ppm to 3.6 ppm. The results shows that milk in Lahore has little to low nutritious value with high contamination. According to analysis it was found that the contamination of Township milk samples in heavy metals (Cr, Fe and Zn) was comparatively high as compared to other towns. The contamination of all the selected heavy metals in milk samples of Data Gang Baksh Town were comparatively low. Keywords: Milk, Heavy metals, Contamination, Low nutrition, Lahore

Heavy Metal Emissions from Coal-fired Power Plants and Heavy Metal Pollution Characteristics and Health Risks in Surrounding Soils

The aim of this study was to reveal the influence of heavy metal emissions from the flue gas of coal-fired power plants on the surrounding soil environment. Seven heavy metals, including As, Cd, Cr, Cu, Pb, Hg, and Ni, were detected in the flue gas of six coal-fired power plants in Shijiazhuang, and the heavy metals in the soil surrounding the power plants were analyzed. The source analysis and health risk assessment of the heavy metals were carried out. The results showed that after a series of flue gas pollutant control measures, the emission concentrations of different heavy metals in the flue gas of the coal-fired power plants ranged from 0.11 to 6.32 mg·(MW·h)-1, and Cu, Cr, and Ni were the main pollutants. The total amount of the seven heavy metal elements discharged into the atmosphere by each power plant was 33.56-275.71 kg·a-1. The average contents of Cr, Cu, Pb, Hg, and Ni in the surface soil surrounding the coal-fired power plant were higher than the background values of Hebei soil, and the contents were 1.16-2.32 times higher than the background values. The heavy metal content in the soil around the power plants was proportional to the heavy metal emissions in the flue gas. The heavy metal content in the soil under different wind directions first increased and then decreased gradually with the increase in distance from the power plants. Source analysis showed that coal combustion emissions contributed the most to heavy metals in soil around the power plants (41.4%), followed by industrial emissions (23.6%) and transportation emissions (19.6%). Altogether, human activities played a leading role in soil heavy metal enrichment, accounting for 84.6%. The health risk assessment showed that the overall health risk of metal elements in the soil surrounding the power plant was within acceptable limits.

Synthesis of nZnO from waste batteries by hydrometallurgical method for photocatalytic degradation of organic pollutants under visible light irradiation.

Waste zinc carbon (Zn-C) batteries are generated worldwide in a large amount. They are non-rechargeable and costly to recycle. Therefore, they end up in the landfills where they create hazards for humans and for environment as well. Zn-C batteries are rich in concentration of different heavy metals so they can be subjected for the recovery of metals for the development of valuable new materials. In this study authors have proposed an easy hydrometallurgical method for the recovery of zinc from waste Zn-C batteries to synthesize nano zinc oxide (nZnO) photocatalyst. The prepared nZnO particles were irregular in shape, highly crystalline in nature with crystallite size 23.94nm. The band gap of the photocatalyst was 3.1eV. The photocatalytic activity of the synthesised nZnO was tested for the degradation of three organic pollutants namely; phenol, p-nitrophenol (PNP) and crystal violet dye (CV) in an aqueous solution under visible light irradiation. nZnO showed a good catalytic efficiency for the degradation of all the three pollutants, however, the crystal violet (CV) removal was best in comparison with the other pollutants, it was minimally effected by the increase in CV concentration. The maximum degradation of phenol, PNP and CV was found to be 95.03±0.2%, 88.63±0.1% and 97.87±0.4%, respectively. The degradation data was fitted best with pseudo-first-order kinetic model. The photocatalyst was recyclable and its regeneration ability was higher for initial three cycles. The intermediate compounds formed in the process of degradation were determined by liquid chromatography and mass spectroscopy (LC-MS) analysis.

Assessment about bioindicator capacity of acrocarpous moss Campylopus schmidii exposed to abandoned pyritic tailings.

Terrestrial mosses are promising species to study concerning metal deposition, absorption, and soil fertility as moss biocrusts. However, acrocarpous moss, as a kind of terrestrial mosses, has not yet been well understood, both in environmental monitoring and ecological application, especially exposed to an abandoned pyrite mining. Herein, we investigated the concentrations of different heavy metals in soil underlying acrocarpous moss Campylopus schmidii at three distances from an abandoned pyrite mine tailings (0.5, 1, 2km) by sampling analysis, as well as the accumulation properties of heavy metals in different parts of mosses and soil nutrients under intact mosses and moss-free layers. The results indicated that the soil we researched was heavily polluted by Cr, Cu, and Cd, which was 4.46, 4.18, and 1.77 times higher than the standard of risk screening values for soil environment quality in China. And there was a marked difference in the concentrations and distribution of heavy metals in mosses, with higher concentrations of Cr, Cu, Ni and Pb mainly in the ageing parts. In addition, mosses can effectively promote soil fertility. Compared with the bare soil without the moss layer, the total organic matter and total potassium concentrations of the soil covered by the intact moss layer were significantly increased, by 113.91% and 186.08% respectively. Correlation analysis indicated that similar pollution sources for Zn, Cd, Cu, and Pb, and the concentrations of these heavy metals in soil connected with the distance from the source of pollution. Overall, we expected that these findings could assess the greater potential of single native dominant moss species C.schmidii to act as biomonitors in specific pyrite mine tailings characterized by barren soil with strong acids (pH<4.0) and polymetallic pollution. Meanwhile, our results revealed may serve as a possibility reference for similar areas and is recommended for developing a vegetative cover utilizing local acrocarpous mosses to achieve greening of degraded tailings in the future, as well as environmental management and protection.

Tolerance and Cadmium (Cd) Immobilization by Native Bacteria Isolated in Cocoa Soils with Increased Metal Content

Twelve cadmium native bacteria previously isolated in soils of cocoa farms located in the western Colombian Andes (Santander), and tolerant to 2500 µM CdCl2 (120 mg Cd/L), were chosen in order to test their tolerance and Cd immobilization using liquid culture medium (Nutritive broth) at different concentrations of heavy metals. Furthermore, in the greenhouse experiments, the strains Exiguobacterium sp. (11-4A), Klebsiella variicola sp. (18-4B), and Enterobacter sp. (29-4B) were applied in combined treatments using CCN51 cacao genotype seeds grown in soil with different concentrations of Cd. All bacterial strains’ cell morphologies were deformed in TEM pictures, which also identified six strain interactions with biosorption and four strain capacities for bioaccumulation; FT-IR suggested that the amide, carbonyl, hydroxyl, ethyl, and phosphate groups on the bacteria biomass were the main Cd binding sites. In the pot experiments, the concentration of Cd was distributed throughout the cacao plant, but certain degrees of immobilization of Cd can occur in soil to prevent an increase in this level in roots with the presence of Klebsiella sp.

Technogenic Pollution of Soils with Heavy Metals and their Accumulation in Leaves and Needles of Forest-forming Species of the Cis-Urals

Forest-forming species of the Cis-Urals (pine, spruce, larch, oak, linden, birch) and soils in forest stands of these species were chosen as study objects. The content of heavy metals (HM) in leaves and needles of forest-forming species, as well as in soils, was analyzed. Different concentrations of HMs were revealed depending on the soil layer. It was shown that adaptations to HM pollution do not depend on whether trees belong to coniferous or deciduous species, which indicates different adaptive potentials of species in each specific case.

Study of the effect of heavy metals and differences of light / dark cycle in the melatonin hormone protein Clock and growth of Neurospora crassa fungi

It was using Neurospora crassa as a model organism to study the biological clock. Due to its use for more than 50 years in the circadian rhythm Study, this biological cycle has been studied by growing it on a Vogel's medium with a constant temperature and different light cycles (continuous light, light to dark, continuous darkness) with different concentrations of heavy metals (Lead Nitrate II, Zinc sulfate, Cadmium chloride, iron chloride III). It was also Measured protein CLOCK and hormone Melatonin By using Elisa Kit. Neurospora crassa was cultured in a thin layer of Vogel's medium using growth tubes (tube race) which grow in one direction only and are distributed by forming conida bands on the medium surface; each band represents one cycle circadian. However, examining Nerospora conidia on growth tubes is a simple but powerful tool for studying the circadian clock and detecting the effect of heavy metals and light on it. At the same time, the results indicated an apparent decrease of CLOCK protein at continuous light compared to light/dark for all treatments. It also recorded a rise in melatonin concentration in continuous darkness and decreased with continuous lighting. The results of the growth tubes also indicated a decrease in growth at continuous light compared to light/dark. Heavy metals also affected Neurospora crassa, as it had the highest inhibition when using lead nitrate II compared to iron chloride III. The study aimed to investigate the effect of heavy metals and differences in light and darkness on the biological clock of the fungus Neurospora crassa.Conclusion the effect on the biological clock disturbances of Neurospora crassa Keywords. Neurospora crassa, Melatonin hormone, Clock protein, Heavy metals, light, dark.

Influence of proline and methyl jasmonate priming on in vitro seed germination and seedling development of Chelidonium majus L

Drought, salinization and heavy metal pollution of soils are main stress factors with an increasing impact on the deterioration of soil quality, yield and crop quality. Seed priming shows good results in improving seed germination, seedling growth and plant development. Proline (Pro) and metyl jasmonate (MeJA) show stimulating activity and help plants overcome stress. The study investigated the effect of Pro, MeJA and hydropriming on seeds sown on water agar supplemented with different concentrations of heavy metals (Cd, Pb, Zn) (HM), NaCl or Polyethylene glycol 6000 (PEG 6000). Chelidonium majus is a medicinal species which is grown as a crop in some parts of Europe. It is an ingredient in some remedies and is becoming an increasingly popular object of research regarding its biological activities. The low concentrations of all heavy metals applied increased the germination of all variants of seeds – control, hydroprimed and those which were Pro and MeJA primed. Seed priming with Pro and MeJA promoted high germination percentage of seeds germinated on water agar with NaCl. PEG 6000 at its higher concentration (5%) slightly increased the seed germination of all variants. The growth of roots and hypocotyls was inhibited by HM and NaCl. However, PEG 6000 slightly influenced their growth.

Effects of heavy metals on fish physiology – A review

The pollution by heavy metals poses a serious threat to the aquatic environment and to the organisms if the concentration of heavy metals in the environment exceeds the safe limits. Due to their non-biodegradable and long persistence nature in the environment, heavy metals cause toxicity in fish by producing oxygen reactive species through oxidizing radical production. In this review, we investigated the effects of heavy metals on fish physiology with special emphasis on hemato-biochemical properties, immunological parameters especially hormones and enzymes, histopathology of different major organs and underlying molecular mechanisms. All those parameters are significantly affected by heavy metal exposure and are found to be important bio-monitoring tools to assess heavy metal toxicity. Hematological and biochemical alterations have been documented including cellular and nuclear abnormalities in different fish species exposed to different concentrations of heavy metals. Major fish organs (gills, liver, kidneys) including intestine, muscles showed different types of pathology specific to organs in acute and chronic exposure to different heavy metals. This study also revealed the expression of different genes involved in oxidative stress and detoxification of heavy metals. In a nutshell, this article shades light on the manipulation of fish physiology by the heavy metals and sought attention in the prevention and maintenance of aquatic environments particularly from heavy metals contaminations.